Gas turbine engines may be used to power aircraft and may include a fan section, a compressor section, a combustor section, a turbine section, and an exhaust section. The fan section is positioned at the front, or “inlet” section of the engine, and includes a fan that induces air from the surrounding environment into the engine. The fan section accelerates a fraction of the air toward the compressor section. The remaining fraction of air is accelerated into and through a bypass plenum, and out the exhaust section. The compressor section raises the pressure of the air it receives from the fan section to a relatively high level. The compressed air then enters the combustor section, where a ring of fuel nozzles injects a steady stream of fuel into the air. The injected fuel is ignited by a burner, which significantly increases the energy of the compressed air. The high-energy compressed air then flows into and through the turbine section, causing rotationally mounted turbine blades to rotate and generate energy. The air exiting the turbine section is exhausted from the engine via the exhaust section, and the energy remaining in this exhaust air aids the thrust generated by the air flowing through the bypass plenum.
Many gas turbine engines, such as the above-described turbofan gas turbine engine, selectively bleed air from the compressor section for the operation of aircraft systems that may be at least partially pneumatically operated. The bleed air may be diverted to a starter control system that may include pneumatically-operated components, such as a pressure relief valve. The pressure relief valve may be used to control an amount of air that is present within the starter control system.
Although the pressure relief valve used in the system is generally well-designed, it may be improved. In particular, in some configurations, the pressure relief valve may include two opposing pre-loaded springs disposed on either side of a spring plate along a single axis. At least one of the springs may be in direct contact with the spring plate. During operation, if a first spring exerts a force against a first side of the spring plate that exceeds a second force exerted by a second spring against a second, opposite side of the spring plate, the spring plate will move toward the second spring. However, because the two springs may move in different directions along a surface of the spring plate, each may deviate from an original position relative to the axis and may exert pressure at different locations on the spring plate. As a result, the pressure relief valve may experience hysteresis, which may decrease a useful life of the components of the valve.
Accordingly, it is desirable to have an improved pressure relief valve that minimizes hysteresis. In addition, it is desirable for the pressure relief valve to be capable of being retrofitted into currently existing engines or aircraft and that may be relatively inexpensive to implement. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.